The invention relates to a device for electronic recording of images with an optical, radiation-emitting system and a detector system for detecting the received image information.
In mordern data technology, images and documents such as written or graphic material are recorded electronically and reproduced on a display or printer. The data received can be reproduced directly or placed in interim storage. The data can be transmitted via data lines, which can span large distances. The data are output by printer units, which work, for example, according to the electro-photographic principle using high-resolution LED arrays. To record the data, the image or document in question is first illuminated. Illumination of the images results in a reflected signal which is picked up by an optical scanner. A detector array, for example, may be used as an optical scanner, said array comprising, for example, detector diodes. The document recording method described involves digitalization of documents in the form of a 1-bit resolution (black/white) or with higher resolution for grey scale recording.
In known methods of electro-optical scanning, the section of the image to be recorded is subjected to uniform and constant illumination. Electronic recording is effected by projecting the image section onto a detector array of sufficiently high resolution which converts the beams reflected off the document into electrical signals. The known electro-optical scanning method has the drawback that a relatively large section of the image has to be illuminated uniformly and constantly to prevent a falsification of the signal due to differing illumination. A further drawback of known electro-optical scanning is that the beams reflected from many points of the image section can generate background interference in the signal.